Smith, David L. MSIE, Purdue University, May 2015. Machining as a Mechanical Property Test Revisited. Major Professor: Srinivasan Chandrasekar. There is much need for data on mechanical behavior of metals at high strains and strain rates. This need is dictated by modeling of processes like forming and machining, wherein the material in the deformation zone is subjected to severe deformation con...

The relationships between the acoustic signal and the modes of the welding pool such as no-keyhole (melt-in), keyhole and cutting in variable polarity plasma arc welding (VPPAW) are investigated. Welch power spectral density (PSD) estimate is used for preprocessing the sound data. A neural network (NN) is used to distinguish the keyhole mode from the cutting mode. The results show that the keyh...

Machining operations of aluminum structural parts are typically carried out under high feeds and high cutting speeds. These cutting conditions exert thermal and mechanical loads on the workpiece, which cause changes in the subsurface material. Residual stresses belong to the machining induced changes and can lead to considerable rejection rates as a consequence of part distortion. Due to the si...

The purpose of this article is to compare time based maintenance (TBM) with condition based maintenance (CBM) relative to cutting tools in the process for removing material. We describe the fault detection (FD), method based on the use of the analytical model of the roughness of the work pieces to be machined. This model is established under given cutting conditions and calculated according to ...

A two-dimensional (2-D) finite element model (FEM) has been developed to perform numerical simulations of vibration assisted machining (VAM). The model is based on an updated Lagrangian formulation, with adaptive remeshing. The model is capable of simulating the amplitude and frequency independently of the tool in the cutting (x) and thrust (y) force directions over a wide range of values. The ...

The surface motif combination, ISO 12085:1996, is a method of analyzing surface texture alternatively to the central line system ‘M’. It gives a graphical evaluation of surface profile using mainly six parameters without filtering waviness from roughness. Another functional roughness characterization is introduced by the DIN 4776 and ISO 13565-2 standards through the ‘’Rk’’ parameters, which de...

This paper investigates the formation of the exit defects in carbon fibre-reinforced plates and characterizes their features in terms of drilling conditions. It was found that spalling and fuzzing are the major mechanisms of exit defects. The spalling, consisting of a main region and a secondary region, is caused by chisel and cutting edge actions, in which the former plays a key role. The fuzz...

The surface finish was extensively studied in usual machining processes (turning, milling, and drilling). For these processes, the surface finish is strongly influenced by the cutting feed and the tool nose radius. However, a basic understanding of tool/surface finish interaction and residual stress generation has been lacking. This paper aims to investigate the surface finish and residual stre...

Determination of optimal cutting parameters is one of the most important elements in any process planning of metal parts. This paper presents a multi-objective optimization technique, based on genetic algorithms, to optimize the cutting parameters in turning processes: cutting depth, feed and speed. Two conflicting objectives, tool life and operation time, are simultaneously optimized. The prop...

The corrosion resistance of magnesium alloys depends mainly on its surface integrity. Previous experimental studies have shown that machining can induces small (nano-scale) grain size, compressive residual stresses and basal plane crystallographic texture, which significantly improve the corrosion resistance of magnesium alloy. These studies have focused on the positive effects of cryogenic coo...